The Sleep Disorders Peter Hauri, PhD Associate Professor of Psychiatry (Clinical Psychology) Director, Dartmouth-Hitchcock Sleep Clinic Dartmouth Medical School Hanover, New Hampshire Contents 5 Introduction The Sleep Laboratory I 5 6 Basic Facts on Sleep Sleep Architecture I 6 Circadian Rhythm I 9 Neurological Basis of Sleep I 12 Age Relationships / 14 Sleep Needs I 15 Total Sleep Deprivation I 18 Deprivation of Specific Sleep Stages I 20 Dream Content I 21 22 Sleep Hygiene Effect of Exercise I 22 Effect oj Environment / 23 Effect of Food I 27 Sleep Medication I 29 34 Specific Sleep Disorders Nosological Considerations / 34 Primary Sleep Disorders I 35 Sleep Disorders Secondary to Medical Problems /53 Sleep Disorders Secondary to Psychiatric Problems I 55 Sleep Disorders Secondary to Behavior Problems / 58 Parasomnias I 63 69 Concluding Comments 70 Bibliography I ~~~g;;r,~z:;:wl"f! Introduction rent moods, electrodes and sensors are applied. At least eight electrodes are Between 12% and 15% of all people needed to determine sleep stages (Recht- living in industrialized countries have schaffen and Kales, 1968): two central- serious sleep problems. This 12% to 15% scalp electrodes (C3 and C4) to record an figure excludes the 20% to 25% of the electroencephalogram (EEG), two at people who complain of occasional bouts the outer canthi of the eyes to record eye of insomnia (Karacan et al, 1976). In a movements (the electro-oculogram, or careful survey of a Florida county, more EOG), two chin electrodes to record a i than 35% of the population reported mentalis electromyogram (EMG), and having trouble sleeping at least "some- two reference electrodes on the earlobes times" and 13% said they had sleep prob- (Al and A2)· However, for a clinical as- lems either "often" or "all the time" sessment of sleep disorders, many more (Karacan et al, 1976). Similar estimates electrodes are usually required. For the I have been obtained ·in other studies evaluation of insomnia, for example. I from this country, from Britain, and one usually needs sensors that measure I· from Australia (Clift, 1975). Further- respiratory rate and breath-by-breath more, problems with insomnia are not air flow, an oxyrneter, EKG leads, and 1 the only sleep disturbances of concern. surface EMG leads over the right and I Excessive daytime sleepiness is a serious left anterior tibialis muscles. On the ! problem for well over 100,000 Americans other hand, a full clinical EEG is rarely (Guilleminault et al, 1974), and prob- obtained in sleep studies. lems during sleep, such as nightmares After electrode application, the sub- and enuresis, take a further toll. ject retires toa relatively quiet and com- The purpose of this review is to help fortable bedroom, which is separate clinicians effectively diagnose and treat from the equipment room but con- patients who complain of sleep prob- nected to it electronically and by an in- lems. Secondarily, it is hoped that crite- tercom system.A technician monitors ria for referring patients to sleep dis- the polysomnogram: the continuous orders centers will be established. To recording of EEG, muscle tension, eye achieve this goal, the review is divided movements, and other activities being into three parts: 1) an introduction to observed. Even though sleep labora- the basic facts of sleep; 2) a review ot the tories traditionally record at only 10 to factors that influence sleep; 3) a discus- 15 mm/sec, an entire night of polysom- sion of the diagnosis and treatment of nography generates from 1,000 to 1,500 the various sleep disorders. feet of paper. Although electronic techniques can The Sleep Laboratory be used to reduce the data, most sleep- Most knowledge concerning sleep in stage analyses are still done by visual humans has been gathered in sleep lab- inspection of the polysomnogram. The oratories, which usually function as fol- classification of sleep stages depends on lows. The subject, either a normal volun- multichannel patterns and relation- teer or a patient suffering from sleep ships rather than on individual EEG disorders, comes to the lab one or two frequencies, and electronic techniques hours before his usual bedtime. After are still less reliable and more expen- the subject fills out a questionnaire con- sive than is the trained eye for this com- cerning his daytime activity and his cur- plex analysis. 5 ~~~- -- - - - ---~.------ "see" (that is. remember or recall) pic- Figun turcs presented to them in this stage (Rechtschaffen and Foulkes, 1965). - Sleepers also change mentally during Basic Facts on Sleep stage 1 as thoughts begin to drift. Think- ing is no longer reality-oriented. and Awak ~ short dreams often develop (Foulkes and Vogel, 1965). Nevertheless, many people Sleep Architecture subjectively feel that they are awake dur- ~ Less than 50 years ago, sleep was thought ing stage 1. Because stage 1 is similar to to be a relatively simple, uniform, and sleep in some respects (lack of reactivity homogenous state. The concept changed to certain stimuli) and similar to wake- in 1935, when Loomis et al described fulness in others (relatively desynchro- Drow; ¥=~ separate and distinct EEG stages within nized EEG), it probably should be con- sleep.The next significant advances sidered a transition phase rather than occurred in the mid-1950s. when Aser- regarded as full sleep (Johnson. 1973). ~tM insky and Kleitman (1953) reported that Stage 2 is marked by the appearance bursts of conjugate. rapid eye move- of sleep spindles (ie, bursts of 12 to 14 ments (REM) periodically appear dur- cycles per second [cps] activity lasting ing sleep and when Dement and Kleit- one half to two seconds) and by K-com- StagE man (1955) linked these periods of REM plexes (well-delineated, slow-negative to dreaming. So, sleep can be looked EEG deflections that are followed by a upon as a complex and multivariable positive component). Stage 2 is the first A/vI, state not unlike a building with various bona fide sleep stage, and mentation components and structural laws relating during this stage usually consists of ••• one part to another. Sleep architecture, short, mundane, and fragmented then, describes the components of sleep thoughts (Foulkes. 1962). (stages, cycles) and their interrelation- Delta sleep is defined by an EEG rec- Stage ships. ord showing at least 20% waves with a Sleep Stages: Basically, there are two frequency of one half to two cps or very different kinds of sleep: Non-Rapid slower and amplitudes greater than Eye Movement (NREM, pronounced 75 microvolts (JtV) peak to peak (C3A2 or Non-Rem) sleep, also called "orthodox" C4Aj). In the past, delta sleep has been sleep or "the Svstate," and Rapid Eye separated further into sleep stages 3 and Movement (REM) sleep. also called 4 depending on the number of delta "paradoxical" sleep or "the D-state" waves. but this differentiation has prov- Within NREM sleep. three stages are en unnecessarily detailed in most cases. Delta usually recognized: stage 1, stage 2, and REM sleep alternates with NREM delta sleep. sleep at about gO-minute intervals. The Stage 1 is a transition phase between EEG pattern during REM resembles full wakefulness and clear sleep. On the that of stage 1 sleep. except that saw- polysomnogram it is identified by a rel- tooth waves are often seen (Figure 1). atively low voltage, mixed-frequency The rapid eye movements (REM), which EEG with a prominence of activity in the give this stage its name, are only one three-to-seven eps range (Rechtschaffen of the outstanding characteristics. Mus- and Kales, 1968). In normal sleepers, de tonus is extremely low (especially stage 1 tends to be relatively short, rang- around the neck and chin), though many ing from one half to seven minutes. small twitches are seen during REM REM Reactivity to outside stimuli is dim in- sleep. Heart rate and respiratory rate ished.For exam pIe, college students are relatively high and very variable. with their eyes taped open no longer More than 80% of subjects awakened 6 i.~~ .~C:_ •• ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~:l ., Figure 7. Human Sleep Stages Awake - low voltage - random, fast 1 sec Drowsy - 8 to 12 cps - alpha waves ,I ,I ,. J , Stage 1 - 3 to 7 cps - theta waves ...•. Stage 2 -12 to 14 cps - sleep spindles and K complexes Delta Sleep - Yz to 2 cps - delta waves> 75 !IV I tI>: i REM Sleep +low voltage - random, fast with sawtooth waves II· Sawtooth Waves Sawtooth Waves .--, r-----. 7 · " j"") 1 ,~ during REM sleep are able to recall Following stage 2, the second REM pe- dreams (Snyder, 1971). riod of the night occurs about three Events during REM sleep are CUSW- hours after falling asleep. This second ,J' marily divided into two classes: tonic REM period lasts about ten minutes and events (such as low muscle tonus and is more intense (both physiologically and desynchronized EEG) that form the sta- psychologically) than the first. ble base of this stage, and phasic events Following the second REM period (such as eye movements and muscle and until awakening in the morning, twitches) that are superimposed in short stage 2 sleep and REM sleep alternate in bursts on this tonic background. about gO-minute cycles. Delta sleep is Sleep Cycles: Upon falling asleep, a rarely seen in these later sleep cycles. subject goes through a stage of relaxed REM periods become more intense wakefulness characterized by alpha (both physiologically and psychological- . waves. Later, the sleeper passes through Iy) and longer towards morning. The stage 1 into stage 2,Gradually descend- mean length of a REM period is' about ing deeper into sleep, most young adults 15 minutes, but REM periods frequently enter delta sleep within 30 to 45 minutes last up to one hour.